plan is having an impact. >>> and yet another milestone for facebook. ceo mark zuckerberg says the social network tops 1 billion active users a month. amounts to half of the world's 2.5 billion users worldwide. despite facebook's troubles on the stock market, those numbers are incredibly remarkable when you kid that less than nine years ago facebook was operating out of a dorm room on harvard's campus. >> you want to catapult something you think of, into this amaze thing from your bedroom. >> a wild back story to it. i am a total, facebook, junkie. totally. i am one of the billion. it's changed the world, in a lot of ways. >> is it too much sharing. i remember, mi-6, security agency in london, that the wife of the agent, the head, the guy heading it up, she posted pictures of him in a bathing suit on face book. running around. got to be careful, privacy settings. >> the thing everybody is worried about, advertising and privacy. going forward. >>> a look at your weather on this holiday weekend. columbus day on monday. stormy and chilly, and in little rock to cincinnati, buffalo.